Lately, the performance of user equipment (UE), such as a smart phone, and mobile communication technology are rapidly developing. Accordingly, a user has become able to access a web server provided by a content provider (CP) and use a variety of content, such as photographs, videos, audio, and applications, through UE at any time and any place. Also, the frequency of using content through a mobile network (e.g., a mobile communication network) in which the mobility of a user is ensured is continuously increasing.
However, while the number of web servers provided by a CP is limited, the number of users who want to access the web servers is rapidly increasing. For this reason, the inventor(s) has noted that various needs related to improve communication resource and quality of service, by reducing, for example, data loss, bottlenecks, transmission delay, and data discontinuity, have occurred. The inventor(s) has noted that to solve these needs, a content delivery network (CDN) has been provided.
A CDN is a service for stably delivering various types of content, such as photographs, movies, and music videos, to one or more UEs. More specifically, the CDN provides cache devices which are widely distributed to major points in a network. The inventor(s) has noted that such cache devices copy and store in advance a part or all of a variety of content, which is content having a large capacity, such as images, videos, and audio, or frequently requested by one or more UEs, present in web servers of a CP far away from the UEs. Subsequently, when a content request message is received from the UEs, a cache device located closest to the UEs transmits content to the UEs. The inventor(s) has noted that the CDN improves content access speed and stably provides content.